• Electrical & Electronic Materials
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• v.9 no.9
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• pp.933-941
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• 1996

In this study, the Tx(Transmitting) and Rx(Receiving) band pass filter for personal communication services was constructed and designed using .lambda./4 TEM mode dielectric resonators. Band pass filter was composed of ceramics resonators which has been developed using ($Zr_{0.65}$,$Sn_{0.35}$) $Ti_{1.04}$ $O_{4.04}$ ceramic and Unloaded-Q ( $Q_{o}$) of .lambda./4 TEM mode dielectric resonator with inner hole size 0.9mm and external size 3mm using silver electrode is 354.5 at 1.95GHz. For the band pass filter design and construction, the design theory and simulation results of band pass filter using J-inverter theory have been studied. The parameters which are evaluated by design theory are practically applied to the filter construction and the simulation results are in agreement with the measured results after fine tunnings.s.s.s.s.s.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.6
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• pp.562-568
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• 2013

This paper presents a design of a wireless power transfer system based on magnetic resonant coupling technology with in-band wireless communication. To increase the transmission distance and compensate for the change in the effective capacitance due to the varying distance, the proposed system used a loop antenna with a selectable capacitor array. Because the increased transmission distance enables multiple charging, we added a communication protocol operated at the same frequency band to manage a network and control power circuits. In order to achieve the efficient bandwidth in both power transfer mode and communication mode, the S-parameters of the loop antennas are adjusted by switching a series resistor. Our test results showed that the loop antenna achieved a high Q factor in power transfer mode and enough passband in communication mode.

• ETRI Journal
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• v.24 no.3
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• pp.190-196
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• 2002

This paper presents millimeter wave monolithic microwave integrated circuit (MMIC) low noise amplifiers using a $0.15{\mu}m$ commercial pHEMT process. After carefully investigating design considerations for millimeter-wave applications, with emphasis on the active device model and electomagnetic (EM) simulation, we designed two single-ended low noise amplifiers, one for Q-band and one for V-band. The Q-band two stage amplifier showed an average noise figure of 2.2 dB with an 18.3 dB average gain at 44 GHz. The V-band two stage amplifier showed an average noise figure of 2.9 dB with a 14.7 dB average gain at 65 GHz. Our design technique and model demonstrates good agreement between measured and predicted results. Compared with the published data, this work also presents state-of-the-art performance in terms of the gain and noise figure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.6
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• pp.532-537
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• 2005

In order to develop a tunable resonator which can be easily operated by DC bias and applied for microwave tunable filters and devices using ferroelectric thin or thick films, the non conductor backed-and conductor backed- coplanar stripline resonators have been designed and analyzed. They have been designed to be operated at 25 GHz which involve coplanar stripline input and output ports. The resonators have been simulated and analyzed using Ansoft HFSS. The research has been focused on the Quality factor of the coplanar stripline resonator. The conductor Q, box Q, and radiation Q of the resonators have been analyzed and calculated according to the substrate thickness & conductor width of the resonators. From these parameters, the loss factors of the coplanar stripline resonator have been investigated. The conducting Q of the coplanar stripline resonator has no relation with the thickness of dielectric substrate and increases as the conductor width increases. The box Q has no much relation with the thickness of substrate and the conductor width, which is above 2000. The radiation loss increases as the thickness of substrate and the conductor width increase. To decrease the radiation loss of the coplanar stripline resonator, a conductor backed coplanar stripline resonator has been proposed which has the unloaded Q of 170.

• Journal of the Microelectronics and Packaging Society
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• v.15 no.1
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• pp.39-44
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• 2008

In this paper, fully embedded 2.4GHz WLAN band pass filter (BPF) was investigated into a multi-layered organic packaging substrate using high Q spiral stacked inductors and high Dk MIM capacitors for low cost RF System on Package (SOP) applications. The proposed 2.4GHz WLAN BPF was designed by modifying chebyshev second order filter circuit topology. It was comprised of two parallel LC resonators for obtaining two transmission zeros. It was designed by using 2D circuit and 3D EM simulators for finding out optimal geometries and verifying their applicability. It exhibited an insertion loss of max -1.7dB and return loss of min -l7dB. The two transmission zeros were observed at 1.85 and 6.7GHz, respectively. In the low frequency band of $1.8GHz{\sim}1.9GHz$, the stop band suppression of min -23dB was achieved. In the high frequency band of $4.1GHz{\sim}5.4GHz$, the stop band suppression of min -l8dB was obtained. It was the first embedded and the smallest one of the filters formed into the organic packaging substrate. It has a size of $2.2{\times}1.8{\times}0.77mm^3$.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.4
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• pp.176-179
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• 2005

The increasing demand for high density packaging technologies and the evolution to mixed digital and analogue devices has been the con-set of increasing research in thin film multi-layer technologies such as the passive components integration technology. In this paper, Cu and TaO thin film with RF sputtering was deposited for spiral inductor and MOM capacitor on the $SiO_2$/Si(100) substrate. MOM capacitor and spiral inductor were fabricated for L-C band pass filter by sputtering and lift-off. We are analyzed and designed thin films L-C passive components for band pass filter at 900 MHz and 1.8 GHz, important devices for mobile communication system. Based on the high-Q values of passive components, MOM capacitor and spiral inductors for L-C band pass filter, a low insertion loss of L-C passive components can be realized with a minimized chip area. The insertion loss was 3 dB for a 1.8 GHz filter, and 5 dB for a 900 MHz filter. This paper also discusses a analysis and practical design to thin-film L-C band pass filter.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.1
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• pp.60-67
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• 2002

In this paper, the dual band VCO of mobile communication terminal using oscillation part switching circuit is proposed. In order to model the VCO accurately, the resonator is converted the equivalent circuit which is analyzed to use numerical method and designed optimal the dual band VCO operating GSM and DCS band. In order to demonstrate the objective theory of the proposed VCO, the dual band VCO is designed and experimented. The results of experiment, it is conformed that the VCO can be used mobile communication hand phone and components of three generation mobile communication systems.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.4
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• pp.131-139
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• 2004

This paper proposes a variable-Q digital graphic equalizer with the opposite filters. A method for designing the proposed equalizer is also presented. In the proposed variable-Q equalizer, we adjust the Q-factor of the equalizer filter depending on the gain, yielding an improved equalizer performance. Also, by increasing the Q-factor of the opposite filters gracefully as the gain becomes greater, the inter-band interference can be removed effectively. We shall show that the frequency response of the proposed equalizer can reproduce the user's gain setting faithfully.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.2
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• pp.134-143
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• 2005

Collagen is the important structural proteins in mammals with various peptide composition and cross-linkings. The direct analysis of collagen protein was not suitable because of its structural complexity and diversity. In this study, we suggest the simple way of collagen analysis by introducing matrix-assisted laser desorption/ionization time-of flight mass spectrometry (MALDI-TOF MS) to identify the collagen and its trypsin-digested fragments, and by subsequent time-of-flight tandem mass spectrometry(Q-TOF MS/MS) to analyze the amino acid sequences of identified fragments. Using the collagen samples extracted from the tail of mouse, 10 separated bands were found in SDS-PAGE, and the masses of most bands could be more finely determined by MALDI-TOF MS. When each 10 separated proteins was tryptic digested and introduced to MALDI-TOF, the Gly1056-Arg1073 fragment from $\alpha_1$-chain was identified in four bands, and the Gly1056-Arg1073 fragment from $\alpha_2$-chain was identified in five bands, both in type I collagen. Although few fragments were found because of the cross-linkings left in digested collagen sample, it could be determined that the type I collagen existed at least in 7 separated bands. When the amino acid sequences of two identified fragments were analyzed by Q-TOF MS/MS, both sequences were identical with those determined by MALDI-TOF MS. It suggested that the two peaks in MALDI-TOF MS caused by the fragments identified in this work could be used as the fingerprint to simply identify type I collagen in protein samples.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.8
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• pp.770-776
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• 2009

We propose and demonstrate an I/Q demodulator using four-port BPSK demodulator base on additive mixing and reflection-type phase shifter using hybrid technique. Previously, the conventional I/Q demodulator base on multiplicative or additive mixing method divides I/Q signal path from mixer to parallel-to-serial converter. In this paper, we propose new I/Q demodulator without dividing I/Q baseband signal path. The proposed schematic requires half size in implementation and half power consumption in baseband path compared with the conventional receiver. Also, the proposed receiver eliminates parallel-to-serial converter after data decoding. The proposed circuit has been successfully demodulated a QPSK signal with the L-band carrier frequency and 20 Mbps data rate.